This invention relates to video generating apparatus and, more particularly, to a system for producing video signals representative of video patterns having operator-selected video attributes.
Apparatus for producing video signals have become quite sophisticated in recent years, and may now include equipment for generating various types of operator-controlled graphics presentations that can be used by themselves, or, for example, in conjunction with keyed-in program video. Modern video graphics equipment has the ability to produce backgrounds, characters, symbols, and other pictorial representations and arrangements in operator-selected sizes, shapes, and colors. Notwithstanding the obvious advantages of having equipment with such sophisticated capabilities, the potential number of users of such equipment is ncessarily limited by the cost which accompanies increasing complexity.
One feature that is particularly desirable in the type of system described is the ability to flexibly generate video backgrounds of operator-selected sizes, locations, and colors. The most common background shape is rectangular; for example, one or more strips or boxes of color background upon which is superimposed television titling or other graphical information. Also, one or more rectangular background areas can be combined to obtain various types of graphics presentations.
It is an object of the present invention to set forth a digital video background generator that provides flexible and versatile operation and is relatively inexpensive to implement. It is another object of this invention to set forth a system which minimizes complexity and cost when employed in apparatus that has interlaced fields in each frame, such as standard NTSC television.